Egg carton



April 28, 1953 ox 2,636,661

EGG CARTON Filed April 15, 1949 2 SHEETS--SHEET 1 W W mm m 37 INVENTOR.

Jo/zrz W C013,

WW W

April 28, 1953 x 2,636,661

EGG CARTON Filed April 15, 1949 2 SHEETS-SHEET 2 JNVENTORf Patented Apr. 28, 1953 EGG CARTON John W. Cox, Chicago, Ill., assignor to Shellmar Products Corporation, Chicago, 111., a corporation of Delaware Application April 15, 1949, SerialNo. 87,789

5 Claims.

The present invention pertains to improvements in foldable, cellular paperboard egg cartons of the general type shown in Troyk Patent No, 1,783,397. The Troyk carton has received wide acceptance in the trade, but occasional instances of carton failure and resultant egg loss occur, usually by crushing under vertical load.

Accordingly, it is a general object of the present invention to provide a foldable paperboard, cell type egg carton of improved structure to increase the strength of the carton, to improve its protection for eggs, and to facilitate the setting-up operation by which the cells are locked into the inside of a cushion-forming bottom.

Another object is to provide such a paperboard egg carton characterized by a novel relationship of its cell-defining cross partitions to a bottom and longitudinal partition-forming structure, whereby the erected cross partitions are held against shifting in a direction longitudinally of the carton and are braced to effectively oppose vertical buckling.

A more specific object of the invention is to provide a paperboard carton including a section which forms a bottom, and a plurality of cross partitions hinged to the front and rear walls of the carton, which partitions are insertable in the bottom section, characterized by the feature of providing the bottom section with pre-formed, partition-receiving slits and with creases serving to afford yieldable flaps or tabs adapted to constitute a stop engageable with the cross partitions disposed in the slits.

It is a still more specific object to provide a carton of the type referred to in the preceding paragraph wherein the tabs are disposed on both sides of the cross partitions and are so formed and related to the cross partitions and to one another that in operative position they engage the partitions in a vertically spaced relation, thereby constituting a force couple acting to brace the partition.

Another object is the provision of a carton of the type described having a wall structure marginally cut out between the spaced bottom and partiton sections to facilitate opening the latter for mutual interlock.

Generally considered, it is an object of the invention to provide a paperboard egg carton of the folda'ble partition type, in which the grain of the paperboard stock characteristically runs in a vertical crosswise direction across the front and rear walls of the carton and in a horizontal crosswise direction across the erected cross par titions, in which carton the cross partitions are so interengaged' with, sustained and braced by the carton bottom as to effectively resist a tendency to buckle about an axis paralleling their direction of grain, thereby greatly rigidifying, stifiening and strengthening the carton as a whole.

The foregoing statements are indicative in a general way of the nature of the invention, but other'and more specific objects will be apparent upon a full understanding of the construction and operation of the device.

Several embodiments of the invention are presented herein for purpose of illustration, and it will be appreciated that the invention is susceptible of incorporation in still other modified forms coming equally within the scope of the appended claims.

In the drawings,

Fig. 1 is a plan view of the flexible paperboard blank from which one embodiment of the carton of the present invention is constructed;

Fig. 1A is a fragmentary plan view, partially broken away, showin the carton in assembled glued condition, prior to being erected to egg re ceiving form;

Fig. 2 is a top plan view of the open carton according to the invention, illustrating the relationship of certain flexible flaps or tabs: in the bottom section of the carton to brace the cross partitions of said carton in the operative, erected or upright position of said partitions;

Fig. 3 is a somewhat enlarged fragmentary View in longitudinal, vertical section along a line gen erally corresponding to line 3-3 of Fig. 2, more clearly illustrating the bracing and stiiiening interaction of the aforesaid flap or tab elements with the cross partitions;

Figs. 4 and 5 are views in vertical transverse section along lines generally corresponding to lines i l and 5-5, respectively, of Fig. 3, further illustrating the relative positions of the cross partitions and the bottom and longitudinal partition forming section of the carton when the latter is erected; and

Figs. 6 and 7 are fragmentary plan views representing alternative, somewhat modified arrangements of cutting and creasing of a blank to produce the interlocked and braced longitudinal cross partition structure of the present invention.

Fig. 1 illustrates a flat paperboard blank which resembles closely the blanks illustrated in the Troyk patent. It includes a bottom and longitudinal partition forming section Ii], which is subdivided by a medial, longitudinally extending crease 1! into equal, complementary panels [2,

hinged by aligned creases 23 on its opposite mart-- gin to a narrow glue flap 24. The section, 22 is further slitted and cut to provide a plurality of identical forked cross partitionslfi; whichepar-titions are individually swingabieaboilt trans-- versely aligned pairs of crease linesZB from a coplanar relationship, shown .l. -to their: operative, erected, and upright positionparallel' to one another. defined by creases 22!, serve to connect the crosspartitionsito=theifront: and-..r.ear lwalls, ill, hi respectivelyswheni thei glueeflaps 24 is. adhered tathalatter. As assembled imknockedown form, the" cross partitions. 2.5r..arefolded-.on. themselves about the medial, longitudinally: extending creases 25'.

The bottom;- and longitudinal partition-ierming section.- til is; provided; with; a longitudinally spacedvseriesi oftransverse; slots 28,-. one. for each cross. partition- 25; which slots are aligned with the cross partition hinges-2161andextendequidistantly on either w side of I the. medial .crease line-ii. iThese.-::slots.-.r.eceive the tcirkedportion of theacrosspartitions z'fiwhenwthe. carton is: in". erectedacendition, as illustrated. in Figs. 2-6. The panels. i2.. i3 one either. .side or: the crease line H are provided with intersectingeslits..29 in order to cushion eggs deposited-.311. the cells between. cross Ea1"titi0nS \2:5'n

.- Referring Y to. Fig; i1, 1 the. bottom section til. is provided with two. parallel: rows of. slittedand creased partition-bracing. formations generally designated 36. These..formationstane.disposed. in pairs whichtare. laterally. .-aligned. with the pairs of cross-partition hinge lines 26, beingaloeated atequaldistances from crease ti... They: are-intendedsfor. the reception otcross partitions .25 and for. bracing. the letterwhen the. cross partitionsuare. swung to. upright position. and .insertedithrough, the. carton. bottom. :30. engaged, the cross partitions are.heldagainstilongitudinail. movement tare-strengthened to resist vertical :buckling'. under. load. As; a,.r.es1ilt, ,the.

carton as: whole is .materially strengthened and. rigidifiedby theimprovedcolumne actionof the. pantitions. .Moreover, thewalls-= t5. and; Li, are rendered highly resistantsto: collapse. by reason oi their integral connection .to thepartitions.

This, may be. accounted. for bytheiact. thatlthe cross partition, resting ana -supporting surface, exerts. a.=w.all suspending. action. at. the; hinge. webs 2.1.. In any-event,.the..walls= [6,. illareenabl'ed to maintain. their original positionunder. vertical loads which, in ordinary Troyl'r cartonstructures or other types of cartons, would .cause..marked outward bulge. or. buckling thereof.

In a preferredv embodiment, the. iformati'onsjfl each. eomprisea somewhat elongated slit illl extending. transversely of thebottom and, partition forming. section. ill, .each slit being intersected at its. opposite .endsby theiangular, longitudinally aligned Ves1its3l2'. The: slittl. is preferably disposed to one side...of atheoreticalline. through .the apices of the .V-slits 32,.i...e.,.0n.theforward or lett=hand sine. Eigskletl. or. intne direction The small triangulamwebstfil' from which the partitions 25 are swung to upright position. The reason for this particular relationship will appear hereinafter. Thus flexible flaps 33, 3d are defined on either side of slit St, the flap 34 being of somewhat larger area than flap 33 because of the off-centering of slit 3!. The flap 34 also is rendered substantially more flexible-with relation, to thapanel 12 or win which. it. is. disposeiias by scoring 35 connecting the ends of slits 32. Flap 33 is not simirlarly scored.

The above features result in the provision of end-narrowed openings 36 (see Fig. 3) to receive the-lower. portionof the cross partitions 25. The .Ilatter are interlochingly engaged with bottom section; :tsahfy;thezmutually in-turned hooks or shoulders-3'! on their lower forked leg portions. 'Openingsfifi are or" course normally closed by the flaps-or tabs 33, 3e.

In assembling the carton from the above described;blank,-the :latter. is: successively folded. on itself; along. creaselines 2.5;. and. i. t. the. glue flap M" is. adhered; to, the. rear Wall it, in. accord;- ance with v the conventional... procedure. This placesthe. carton inits flat. knockededown con: dition. for shipment. or. storage.

In the: collapsed..carton, as shownin IA, the rear. .Gllerhalf of. the. cross. partition. section and therear onei-hali of the; bottom: section are spaced... apart-by a, portion. .of' the rear" wall [8. The. rear wallis, marginally cut away at'fij at a. point. between. the .erossgpartition. section and the cuts. 3.5., till ofthebottomlsection. Inerecting the carton, .it. is placed. With it'sback. side down andlield. in suchposition by restraining thecover section. i 9.. The. front. wall is. engaged opposite the cut-out. 3tiand liitedupwardly to initiate. spreadingthe. walls...apart -.at end .of thecarton. Thespreadingaction then. is. progressed the. length of. the carton to. present the partitions. andbottom. section in upright position so that the bottom may be pushed in and engaged with thepartitions when. the latter. are. rotated into. cross position.

' The. carton. erected by causing the. front. and rear wallsit', i'l', thebottom and. longitudinal partition. section iii, and crosspartitionpanel 22 to assume a generally rectangular outline.v The crosspartitions 25: are then swung to. the operativeupright. position illustrated Figs. 2. through 5;, the. bottom. section it is "bent. upwardly. along medial crease iii-to.-

thetwo-walled 1011.- gitudinal partition of the carton, .designatedtt, and the..cross.partitiens. are. interlocked .inthe openingsfit. adjoining. the. formations 3l 01sec..- tionill. by means of. the. inturned. cross. partition. hook elements .ti. The cross partitions are guided into theopenings 35 andare positioned properly in, a plane. extending between theapices of. V-slits as bytheopposedang-led or v-shaped margins ofthe openings 36.. Additional guiding action is performed by the flaps 33,36. nsthe ends of the. cross partitions hit the trap. doorsv 33 and 3t duringth-e looking operation, these doors are deflected outwardly, therebydefiectingthe partitions towardthe centerotthe openingstb in case the partitions are slightly outpi alignment.

The particular. arrangement and configuration of the. cross partition-receiving formations 36 cause. thev respective flaps 33, 34- thereoftobe deflected difierently when .the cross partitions are. inserted therein. Inasmuch as. the rearward flap 3. has agreater degree of flexibility..-than flan. 33.... it naturally displaced iarther down.-

ward than the flap 33, as shown in Figs. 3 and 4. The flap 33 usually assumes a position fairly closely adjacent the plane of the adjacent bottom section area and the flap 34 is bent substantially farther down. Though their exact individual disposition will naturally vary, the two flaps generally assume positions which are in substantially vertically spaced relation to one another (see Fig. 3) on opposite sides of partition 25.

In the preferred form, the rear flap, i. e., that located on the side of the slit 3! toward which the cross partition swings, engages the partition well below the other flap, and the two flaps have direct frictional engagement with said partition at two points to brace the same. Bending the cross partitions into erect position about the hinges 26 causes the partitions to tend to bulge outwardly in resisting the bend, thereby reducing their vertical rigidity. The trap-door 34 braces the outer end of each partition, and the trapdoor 33 pushes the partition inwardly on the side of the partition toward which the partition tends to bulge. Accordingly, the cross partition is effectively braced in vertical position to present maximum column strength. Its lower edges lie approximately in the horizontal plane of the bottom margins of walls l6, [1, so as to rest on a supporting surface, and its upper extremity is abutted by the cover 19; hence, it coacts positively with and tends to support the walls in resisting crushing forces on the carton. Due to their integral connection with said walls and their engagement with a supporting surface, the cross partitions exert a pronounced vertical suspending and reinforcing action on the front and rear walls, substantially increasing their resistance to buckling under vertical compression.

The bracing of the cross partitions 25 by flaps 33, 34 also has the function of offsetting a tendency to vertical buckling which arises because of the normal direction of grain of the paperboard stock. Inasmuch as the grain extends transversely of the blank, 1. e., in the direction of the double headed arrows shown in Fig. 1, it follows that, when the cross partitions 25 are swung downwardly to operative, upright position, the grain thereof runs horizontally (see the arrows in Figs. 4 and The tendency of the cross partitions to bulge laterally or buckle is thus normally aggravated by the horizontal disposition of their grain structure. However, in the present carton a force couple is exerted on the partition to substantially stiffen the latter vertically. Moreover, the direct engagement of the fiaps or bottom section edges with the opposite sides of the cross partition in effect reduces the height of the cross partition which is subject to bulging. Still further, due to the fact that the above described formations 30 are formed in the upwardly convergent panels I 2, l3 of the bottom and longitudinal partition section l0, it follows that the engagement of the cross partition by the flaps 33, 34 is along a line extending upwardly and inwardly of the carton, i. e., diagonally of the grain of the cross partitions. This still further extends the stiffening and buckle resisting effect of the provisions described.

As mentioned above, it is desirable in the erection of the carton to deflect the rearmost flaps 34 farther downwardly than the flaps 33. The embodiment of Figs. 1 to 5 inclusive relates to a type of formation which-has this function. The sameresult may be accomplished by an appropriate adjustment in the timing of the carton set-up machine which is usually employed for the purpose of automatically erecting structures of this type to produce deflection of the bracing flaps in different degree. Other embodiments of the invention are shown in Figs. 6 and 7.

The embodiment of Fig. 6 is generally similar in structure and function to that of Figs. 1 to 5 inclusive. In this case, the formation includes a left-hand flap structure in the form of a plurality of small flexible tongues 4| outlined by parallel cuts 42 terminating at the medial slit 43. The other flap 44 is similar to the flap 34 and the slit 43 joins the opposed V-shaped slits 45 on the forward side of the apex thereof.

In the modification of Fig. 7 a single transverse slit 48 is caused to intersect the termini of a pair of opposed angled cuts 49 immediately to one side of the opposite apices of said cuts. This defines a single flap 50 hinged by a crease line 5| to the bottom structure and adapted to engage and brace a cross partition at a depressed point relative to the remainder of the bottom panel of the carton.

Those skilled in the art will readily perceive the feasibility or desirability of various further alterations and modifications of the above described concept, without departing from the principles of the invention. The invention accomplishes a substantial reinforcement and rigidification of a partitioned cell type carton, as a whole, by the direct side bracing and confinement of its constituent partitions at their points of penetration of the carton bottom, accomplished by a force couple. I therefore desire that the invention be construed in this light, and no more limitedlythan is reasonably consistent with the language of the appended claims.

Iclaimf 1. A paperboard egg carton comprising front and rear walls integrally connected by a bottom section having a plurality of slits between said front and rear walls, said slits including straight portions extending transversely of said bottom section and longitudinal portions extending from the opposite termini of said straight portions, and transversely extending cross partitions disposed. in the erected condition of the carton, in upright position relative to said bottom section, said cross partitions being hingedly connected to said front and rear walls and the lower portions thereof penetrating the slits in said bottom section when in said upright position, an edge of the material defined by one of said slits being adapted for engagement with a side of one of said cross partitions in a direction normal to its plane and a plane different from that of said penetrated section, the material of said bottom section being of differing flexibility on opposite sides of said tnansverse slits, whereby to engage said cross partitions at different vertical levels, the lower extremities of said cross partitions being substantially coplanar with the lower margins of said walls to sustain the latter through the hinged wall and partition connections when the carton rests on a supporting surface, the engagement of said cross partitions in different vertical planes by said bottom section providing a force couple resisting horizontal buckling of said cross partitions under vertical compressive load transmitted through the latter.

2. A collapsible paperboard egg carton comprising front and rear walls integrally and marginally connected by a bottom section, said bottom section being provided between said front rowl-e61 extenain tran versely of -saidibottorn:.s tion and longitudinal, portions, extending irom. the opp si e-termini l n i i f s raight oorti na and 'ao v lv ext nding erossnp r itions di po es, in. he erecterloonditmnot the r on, in p igh P sition relative. tmsaid walls and bottomsecion; said. orosswnartitions each e g hinee iy connected, to said; front anclyrear walls and the lower gortions, of said cross: partitions; penetrating...s.aid bottom. section, slits, .saiciresoe tiv cro s-partitions bei g. posi ively enga ed and braoeriqby b. adia en edge/oi said. re pective fie iormati. ea. ale. fiaoiormations b ing di .Qlmfid; from. the'pla-ne of. Saiol bottom section when sorengaged, the material of said bottom section being of differing flexibility on opposite sides; of saiitransverse; slits, whereby to engage said-cross, partitions at different vertical, levels, the lowerextremities of said cross partitions being substantially coplanar with the lowerrriarginsk of -sa irl walls to sustain the latter through the hingedwall and-1 partition connections when the car-ton rests ona supporting surface, the engagement o-isaid respective cross partitions in difierentivertical planes lay-said bottom section and ,fiapiiormations thereof providing a force coupleresisting horizontalbuckling of said, cross partitions under Vertical compressive load. transmittedithroughthe. latter.

3., A paperboard egg carton. comprising front and rear Walls inte rally onnect d a ja n th ir lower margins. by abottomsection, said. bottom section being provided. betwe n said front and rear Wall margin l. connection thereof with transverse slits, each of which is defined by a set of opposeclfl xible. flap f rmationa. said sli s including straiehtnortion .extend. ransv rse 1y of. said. bot om ection and longitudfmal. portions extending. from thev opnosite termini of said straight portions, and, transversely extending cross partitions. disposed,v in the. erected condition of the carton, in upright, position. relative to said bottom. section, said cross partitions each being hingedly ,connectedto the. saidgfront. and rear walls andthe lower portions. of said. cross partitions penetrating a. substantial. distance through said bottom section slits, saidcross. partitions being positivelyengageeland braeedby ad.- 12340831 edges ofsaid. flap formationsand. one of id formations of. each setbeing clefleeteddownwar lly y its r sp ctive. r sspartition too. gr at.-

exten than. th th r; he ma erial. ofs icl b ttom secti n; being; of, .difierine flexibility on opp site des of saidtransverse slita, wher by o en a e d'goross partit n t. ciifferentv rtical levels, the lower extremities of said cross partitions being substantially coplanar with, the lowor margins of said walls to: sustain the latter through the hinged Wall, engagement of said cross partitions in different vertical planes by said respeotive adjacent flapformations providing; ,a for e. oupl r si in hor zont lbuckling of. said. Cross par i ions under. vertical compressive load transmitted through the latter.

A oll psibl p p r-board ee carton. com.- iirisir e fr nt and rear walla a bottom conne in Walls and; ncud rieyinwardly. and upwardly Qov reent. lone ini a partition. sections and cros partitio hin e tolsa d, vrallsiadiacentzthe timer m .he leofi; for. swineina: movementsto an. uoriebtrnositionr said. b ttom. being provided ,w th pairs wot aligned, transverse: slits; eachrof which slits: is su stantially joined; at: itsendsiby fur her-slits atan acute ngl thereto-redefine a cross partition. receivi opening havinea flesible trapdoor flap; formation on at. leastroneside thereof, saidrespective cross artiticns .bei;napro l ressi-vely guided by. said acute: angled. flan tor.- mations, toward and: into said op n esandwhen so'oositioned'zbeins po i v y nga ed, ami braced by said formations above the lower free marg ns thereof, the material of said bottom: section bein of differing fieX-ibilityon opposite sides of. said. trans-verse slits, wh re y o n age aid. cross partitions at, different. vertical levels, the-extremities of. sai il wer fre mar ns ly ng-substantially p ana :wi h he lower margins of. said wallsto sustain thezlatterp through: the hinged; Welland partition; connections: when the carton rests on. a sup gicirtingsurface, said respective fiap-liormar tionsengaging said respectivecross partitions along lines. vertically spaced relation to linessof engagementoi the, opposite side thereof by the remainder of the, bottom, and provi linea force uple atsaiol re pe t v lin s of. en a ement re.- sisting horizontal buckling of said cross; partitions under vertical load transmitted through the: latter.

5..A c llapsibl paperboardegg oartoncomprising; front anclrear walls, a bottom connectin said walls and: including inwardly" and upwardly convergent, longitudinal, partition. sections, and cross partitions h-ingecl-v to said walls adjacent the upper margin. thereof for swinging; movement" 1 an upright position, said-bottom being provided with pairs of aligned, transverse. slits,;oa,ch, of which. slits is-siibstantially joined at its ends; by further slits at an acute; angle. thereto; to. deli N cross partition receiving; opening havinga'fie H b, trap d oirfiapiform tion on achid there saiel cross partitions, being progressively gidedb-y saidacuteangled flap formations towarol and. into said openings and when so positioned being positively engaged and braced by said formations above the. lower, free margins thereof,- one of said flap formations being more flexible than the other whereby said iiormations assume va vertically spaced relation when operativelyengaged with a cross partition, the material of said: bottom sec.- tion being of difiering flexibility on opposite sides of said transverse slits, whereby to engage; said cross partitions. at different vertical levels, the extremities of saidlower free margins lying sub,- stantially coplanar with thelower niargms o5 said walls to sustain the latter through the hinged Welland partition connections when the carton rest on a supportin f en ag m nt oi said cross partitionsatdifierent verticals, elevationaby saidrespective flap. formations providing; a io ce couple-resisting horizontal buckling of said. cross p rtitions, under vertical compressivel ad t ansmitted; throi e'hthe latter.

JOHN

References Cited in the file of this patent U TED. STATES ATE TS.-

.Ztillfiii l: .1 real or. lon 104.19.43 meager. .Benoi Mud-ma: E0. 35);; 1.9. 3 2e e7fli2l3. Goa... imam. Aug; 16,11,949 

